My best buddy is about the most frugal person I know! She is one of the coupon finatics that won’t pay full price for anything. For this reason, when it came time to update area of her central A/C method she started searching for the best deal she could find. This method works in most cases, but, splitting corners when it comes to something as important as your HVAC method can end up costing you more in the long run, this is exactly what happened. She found someone selling a “scratch & dent” heat pump. This is the exterior unit for her system. It was a different brand from the indoor air handler she had, however she said that they could make it work. Making it work, & making sure it is efficient, are 2 honestly different things. Yes, the professional could connect the 2 pieces together, & yup, it would cool her house, however it ended up costing her on her energy bills. When she called the HVAC supplier they told her that the 2 units were not designed to task together. This affected the air flow & caused the increase in her energy bills. The supplier told her that this was the reason he consistently commanded replacing both units at the same time. Making sure that the 2 components were designed to task together was important to ensure the performance that you wanted. She l received a particularly overpriced lesson from this whole ordeal. It isn’t consistently about the initial cost & occasionally, spending the extra currency upfront, can save you significantly in the long run.